I've been keeping this under wraps for a while, but my next book series will be about trains and because I don't know that much about them, I've persuaded the talented and lovely Sam Sedgman to write them with me.

Sam is a playwright and digital producer that I worked with at the National Theatre. He's obsessed with mysteries and railways, which will come in handy when we are creating our adventures on trains for you to read.

I'm very excited about these books. They will be published by Macmillan in 2020 and are going to be epic!

The books will follow 11-year-old Harrison Beck and his uncle, travel writer Nathaniel Bradshaw, as they travel the great railways of the world and encounter all manner of mysteries and adventures. The first book, The Highland Falcon, follows Harrison and Uncle Nat on board the last journey of the royal steam train. Among the passengers are aristocrats, actors and businessmen... and a very clever jewel thief.